Mar*_*nnw 3 android xamarin.android android-activity
我知道OnActivityResult应该在一个Activity中的OnResume之前立即调用,但这不会发生在我身上.我发现它在OnResume之前被调用,甚至在OnStart之前.我的示例代码如下,我正在查看相关方法,以了解发生了什么.这是怎么回事?
using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content.PM;
namespace LifecycleTest
{
[Activity(MainLauncher = true)]
public class Activity1 : Activity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.Main);
this.FindViewById<Button>(Resource.Id.button1).Text = "Start Activity 2";
this.FindViewById<Button>(Resource.Id.button1).Click += button_Click;
}
void button_Click(object sender, EventArgs e)
{
Intent i = new Intent(this, typeof(Activity2));
this.StartActivityForResult(i, 1);
}
protected override void OnStop()
{
base.OnStop();
}
protected override void OnResume()
{
base.OnResume();
}
protected override void OnStart()
{
base.OnStart();
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
}
}
}
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using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content.PM;
namespace LifecycleTest
{
[Activity]
public class Activity2 : Activity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.Main);
this.FindViewById<Button>(Resource.Id.button1).Text = "Return Result";
this.FindViewById<Button>(Resource.Id.button1).Click += button_Click;
}
void button_Click(object sender, EventArgs e)
{
this.SetResult(Result.Ok);
this.Finish();
}
}
}
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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:minWidth="25px"
android:minHeight="25px">
<Button
android:text="Button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/button1" />
</LinearLayout>
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看之前android.app.ActivityThread#performResumeActivity
它调用的是API-23 .#deliverResults()
Activity#performResume()
前者最终会打电话,Activity#onActivityResult()
而后者Activity#onStart()
如果尚未开始则会打电话.因此,调用的顺序将是:
onActivityResult()
onStart() // only if it has been stopped
onResume()
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这似乎是回到Android 2.0的情况.虽然有帖子声称不然.
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